samples/bpf: Convert XDP samples to libbpf usage

Some of XDP samples that are attaching the bpf program to the interface
via libbpf's bpf_set_link_xdp_fd are still using the bpf_load.c for
loading and manipulating the ebpf program and maps. Convert them to do
this through libbpf usage and remove bpf_load from the picture.

While at it remove what looks like debug leftover in
xdp_redirect_map_user.c

In xdp_redirect_cpu, change the way that the program to be loaded onto
interface is chosen - user now needs to pass the program's section name
instead of the relative number. In case of typo print out the section
names to choose from.

Signed-off-by: Maciej Fijalkowski <[email protected]>
Reviewed-by: Jakub Kicinski <[email protected]>
Acked-by: Jesper Dangaard Brouer <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>

Author: Maciej Fijalkowski

samples/bpf/Makefile

@@ -87,18 +87,18 @@ test_cgrp2_sock2-objs := bpf_load.o test_cgrp2_sock2.o
 xdp1-objs := xdp1_user.o
 # reuse xdp1 source intentionally
 xdp2-objs := xdp1_user.o
-xdp_router_ipv4-objs := bpf_load.o xdp_router_ipv4_user.o
+xdp_router_ipv4-objs := xdp_router_ipv4_user.o
 test_current_task_under_cgroup-objs := bpf_load.o $(CGROUP_HELPERS) \
 				       test_current_task_under_cgroup_user.o
 trace_event-objs := bpf_load.o trace_event_user.o $(TRACE_HELPERS)
 sampleip-objs := bpf_load.o sampleip_user.o $(TRACE_HELPERS)
 tc_l2_redirect-objs := bpf_load.o tc_l2_redirect_user.o
 lwt_len_hist-objs := bpf_load.o lwt_len_hist_user.o
-xdp_tx_iptunnel-objs := bpf_load.o xdp_tx_iptunnel_user.o
+xdp_tx_iptunnel-objs := xdp_tx_iptunnel_user.o
 test_map_in_map-objs := bpf_load.o test_map_in_map_user.o
 per_socket_stats_example-objs := cookie_uid_helper_example.o
-xdp_redirect-objs := bpf_load.o xdp_redirect_user.o
-xdp_redirect_map-objs := bpf_load.o xdp_redirect_map_user.o
+xdp_redirect-objs := xdp_redirect_user.o
+xdp_redirect_map-objs := xdp_redirect_map_user.o
 xdp_redirect_cpu-objs := bpf_load.o xdp_redirect_cpu_user.o
 xdp_monitor-objs := bpf_load.o xdp_monitor_user.o
 xdp_rxq_info-objs := xdp_rxq_info_user.o

samples/bpf/xdp_redirect_cpu_user.c

@@ -24,12 +24,8 @@ static const char *__doc__ =
 /* How many xdp_progs are defined in _kern.c */
 #define MAX_PROG 6
 
-/* Wanted to get rid of bpf_load.h and fake-"libbpf.h" (and instead
- * use bpf/libbpf.h), but cannot as (currently) needed for XDP
- * attaching to a device via bpf_set_link_xdp_fd()
- */
 #include <bpf/bpf.h>
-#include "bpf_load.h"
+#include "bpf/libbpf.h"
 
 #include "bpf_util.h"
 
@@ -38,6 +34,15 @@ static char ifname_buf[IF_NAMESIZE];
 static char *ifname;
 
 static __u32 xdp_flags;
+static int cpu_map_fd;
+static int rx_cnt_map_fd;
+static int redirect_err_cnt_map_fd;
+static int cpumap_enqueue_cnt_map_fd;
+static int cpumap_kthread_cnt_map_fd;
+static int cpus_available_map_fd;
+static int cpus_count_map_fd;
+static int cpus_iterator_map_fd;
+static int exception_cnt_map_fd;
 
 /* Exit return codes */
 #define EXIT_OK		0
@@ -52,7 +57,7 @@ static const struct option long_options[] = {
 	{"dev",		required_argument,	NULL, 'd' },
 	{"skb-mode",	no_argument,		NULL, 'S' },
 	{"sec",		required_argument,	NULL, 's' },
-	{"prognum",	required_argument,	NULL, 'p' },
+	{"progname",	required_argument,	NULL, 'p' },
 	{"qsize",	required_argument,	NULL, 'q' },
 	{"cpu",		required_argument,	NULL, 'c' },
 	{"stress-mode", no_argument,		NULL, 'x' },
@@ -70,7 +75,17 @@ static void int_exit(int sig)
 	exit(EXIT_OK);
 }
 
-static void usage(char *argv[])
+static void print_avail_progs(struct bpf_object *obj)
+{
+	struct bpf_program *pos;
+
+	bpf_object__for_each_program(pos, obj) {
+		if (bpf_program__is_xdp(pos))
+			printf(" %s\n", bpf_program__title(pos, false));
+	}
+}
+
+static void usage(char *argv[], struct bpf_object *obj)
 {
 	int i;
 
@@ -88,6 +103,8 @@ static void usage(char *argv[])
 				long_options[i].val);
 		printf("\n");
 	}
+	printf("\n Programs to be used for --progname:\n");
+	print_avail_progs(obj);
 	printf("\n");
 }
 
@@ -262,7 +279,7 @@ static __u64 calc_errs_pps(struct datarec *r,
 
 static void stats_print(struct stats_record *stats_rec,
 			struct stats_record *stats_prev,
-			int prog_num)
+			char *prog_name)
 {
 	unsigned int nr_cpus = bpf_num_possible_cpus();
 	double pps = 0, drop = 0, err = 0;
@@ -272,7 +289,7 @@ static void stats_print(struct stats_record *stats_rec,
 	int i;
 
 	/* Header */
-	printf("Running XDP/eBPF prog_num:%d\n", prog_num);
+	printf("Running XDP/eBPF prog_name:%s\n", prog_name);
 	printf("%-15s %-7s %-14s %-11s %-9s\n",
 	       "XDP-cpumap", "CPU:to", "pps", "drop-pps", "extra-info");
 
@@ -423,20 +440,20 @@ static void stats_collect(struct stats_record *rec)
 {
 	int fd, i;
 
-	fd = map_fd[1]; /* map: rx_cnt */
+	fd = rx_cnt_map_fd;
 	map_collect_percpu(fd, 0, &rec->rx_cnt);
 
-	fd = map_fd[2]; /* map: redirect_err_cnt */
+	fd = redirect_err_cnt_map_fd;
 	map_collect_percpu(fd, 1, &rec->redir_err);
 
-	fd = map_fd[3]; /* map: cpumap_enqueue_cnt */
+	fd = cpumap_enqueue_cnt_map_fd;
 	for (i = 0; i < MAX_CPUS; i++)
 		map_collect_percpu(fd, i, &rec->enq[i]);
 
-	fd = map_fd[4]; /* map: cpumap_kthread_cnt */
+	fd = cpumap_kthread_cnt_map_fd;
 	map_collect_percpu(fd, 0, &rec->kthread);
 
-	fd = map_fd[8]; /* map: exception_cnt */
+	fd = exception_cnt_map_fd;
 	map_collect_percpu(fd, 0, &rec->exception);
 }
 
@@ -461,7 +478,7 @@ static int create_cpu_entry(__u32 cpu, __u32 queue_size,
 	/* Add a CPU entry to cpumap, as this allocate a cpu entry in
 	 * the kernel for the cpu.
 	 */
-	ret = bpf_map_update_elem(map_fd[0], &cpu, &queue_size, 0);
+	ret = bpf_map_update_elem(cpu_map_fd, &cpu, &queue_size, 0);
 	if (ret) {
 		fprintf(stderr, "Create CPU entry failed (err:%d)\n", ret);
 		exit(EXIT_FAIL_BPF);
@@ -470,23 +487,22 @@ static int create_cpu_entry(__u32 cpu, __u32 queue_size,
 	/* Inform bpf_prog's that a new CPU is available to select
 	 * from via some control maps.
 	 */
-	/* map_fd[5] = cpus_available */
-	ret = bpf_map_update_elem(map_fd[5], &avail_idx, &cpu, 0);
+	ret = bpf_map_update_elem(cpus_available_map_fd, &avail_idx, &cpu, 0);
 	if (ret) {
 		fprintf(stderr, "Add to avail CPUs failed\n");
 		exit(EXIT_FAIL_BPF);
 	}
 
 	/* When not replacing/updating existing entry, bump the count */
-	/* map_fd[6] = cpus_count */
-	ret = bpf_map_lookup_elem(map_fd[6], &key, &curr_cpus_count);
+	ret = bpf_map_lookup_elem(cpus_count_map_fd, &key, &curr_cpus_count);
 	if (ret) {
 		fprintf(stderr, "Failed reading curr cpus_count\n");
 		exit(EXIT_FAIL_BPF);
 	}
 	if (new) {
 		curr_cpus_count++;
-		ret = bpf_map_update_elem(map_fd[6], &key, &curr_cpus_count, 0);
+		ret = bpf_map_update_elem(cpus_count_map_fd, &key,
+					  &curr_cpus_count, 0);
 		if (ret) {
 			fprintf(stderr, "Failed write curr cpus_count\n");
 			exit(EXIT_FAIL_BPF);
@@ -509,8 +525,8 @@ static void mark_cpus_unavailable(void)
 	int ret, i;
 
 	for (i = 0; i < MAX_CPUS; i++) {
-		/* map_fd[5] = cpus_available */
-		ret = bpf_map_update_elem(map_fd[5], &i, &invalid_cpu, 0);
+		ret = bpf_map_update_elem(cpus_available_map_fd, &i,
+					  &invalid_cpu, 0);
 		if (ret) {
 			fprintf(stderr, "Failed marking CPU unavailable\n");
 			exit(EXIT_FAIL_BPF);
@@ -530,7 +546,7 @@ static void stress_cpumap(void)
 	create_cpu_entry(1, 16000, 0, false);
 }
 
-static void stats_poll(int interval, bool use_separators, int prog_num,
+static void stats_poll(int interval, bool use_separators, char *prog_name,
 		       bool stress_mode)
 {
 	struct stats_record *record, *prev;
@@ -546,7 +562,7 @@ static void stats_poll(int interval, bool use_separators, int prog_num,
 	while (1) {
 		swap(&prev, &record);
 		stats_collect(record);
-		stats_print(record, prev, prog_num);
+		stats_print(record, prev, prog_name);
 		sleep(interval);
 		if (stress_mode)
 			stress_cpumap();
@@ -556,17 +572,51 @@ static void stats_poll(int interval, bool use_separators, int prog_num,
 	free_stats_record(prev);
 }
 
+static int init_map_fds(struct bpf_object *obj)
+{
+	cpu_map_fd = bpf_object__find_map_fd_by_name(obj, "cpu_map");
+	rx_cnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rx_cnt");
+	redirect_err_cnt_map_fd =
+		bpf_object__find_map_fd_by_name(obj, "redirect_err_cnt");
+	cpumap_enqueue_cnt_map_fd =
+		bpf_object__find_map_fd_by_name(obj, "cpumap_enqueue_cnt");
+	cpumap_kthread_cnt_map_fd =
+		bpf_object__find_map_fd_by_name(obj, "cpumap_kthread_cnt");
+	cpus_available_map_fd =
+		bpf_object__find_map_fd_by_name(obj, "cpus_available");
+	cpus_count_map_fd = bpf_object__find_map_fd_by_name(obj, "cpus_count");
+	cpus_iterator_map_fd =
+		bpf_object__find_map_fd_by_name(obj, "cpus_iterator");
+	exception_cnt_map_fd =
+		bpf_object__find_map_fd_by_name(obj, "exception_cnt");
+
+	if (cpu_map_fd < 0 || rx_cnt_map_fd < 0 ||
+	    redirect_err_cnt_map_fd < 0 || cpumap_enqueue_cnt_map_fd < 0 ||
+	    cpumap_kthread_cnt_map_fd < 0 || cpus_available_map_fd < 0 ||
+	    cpus_count_map_fd < 0 || cpus_iterator_map_fd < 0 ||
+	    exception_cnt_map_fd < 0)
+		return -ENOENT;
+
+	return 0;
+}
+
 int main(int argc, char **argv)
 {
 	struct rlimit r = {10 * 1024 * 1024, RLIM_INFINITY};
+	char *prog_name = "xdp_cpu_map5_lb_hash_ip_pairs";
+	struct bpf_prog_load_attr prog_load_attr = {
+		.prog_type	= BPF_PROG_TYPE_UNSPEC,
+	};
 	bool use_separators = true;
 	bool stress_mode = false;
+	struct bpf_program *prog;
+	struct bpf_object *obj;
 	char filename[256];
 	int added_cpus = 0;
 	int longindex = 0;
 	int interval = 2;
-	int prog_num = 5;
 	int add_cpu = -1;
+	int prog_fd;
 	__u32 qsize;
 	int opt;
 
@@ -579,22 +629,25 @@ int main(int argc, char **argv)
 	qsize = 128+64;
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	prog_load_attr.file = filename;
 
 	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
 		perror("setrlimit(RLIMIT_MEMLOCK)");
 		return 1;
 	}
 
-	if (load_bpf_file(filename)) {
-		fprintf(stderr, "ERR in load_bpf_file(): %s", bpf_log_buf);
+	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
 		return EXIT_FAIL;
-	}
 
-	if (!prog_fd[0]) {
-		fprintf(stderr, "ERR: load_bpf_file: %s\n", strerror(errno));
+	if (prog_fd < 0) {
+		fprintf(stderr, "ERR: bpf_prog_load_xattr: %s\n",
+			strerror(errno));
+		return EXIT_FAIL;
+	}
+	if (init_map_fds(obj) < 0) {
+		fprintf(stderr, "bpf_object__find_map_fd_by_name failed\n");
 		return EXIT_FAIL;
 	}
-
 	mark_cpus_unavailable();
 
 	/* Parse commands line args */
@@ -630,13 +683,7 @@ int main(int argc, char **argv)
 			break;
 		case 'p':
 			/* Selecting eBPF prog to load */
-			prog_num = atoi(optarg);
-			if (prog_num < 0 || prog_num >= MAX_PROG) {
-				fprintf(stderr,
-					"--prognum too large err(%d):%s\n",
-					errno, strerror(errno));
-				goto error;
-			}
+			prog_name = optarg;
 			break;
 		case 'c':
 			/* Add multiple CPUs */
@@ -656,33 +703,45 @@ int main(int argc, char **argv)
 		case 'h':
 		error:
 		default:
-			usage(argv);
+			usage(argv, obj);
 			return EXIT_FAIL_OPTION;
 		}
 	}
 	/* Required option */
 	if (ifindex == -1) {
 		fprintf(stderr, "ERR: required option --dev missing\n");
-		usage(argv);
+		usage(argv, obj);
 		return EXIT_FAIL_OPTION;
 	}
 	/* Required option */
 	if (add_cpu == -1) {
 		fprintf(stderr, "ERR: required option --cpu missing\n");
 		fprintf(stderr, " Specify multiple --cpu option to add more\n");
-		usage(argv);
+		usage(argv, obj);
 		return EXIT_FAIL_OPTION;
 	}
 
 	/* Remove XDP program when program is interrupted or killed */
 	signal(SIGINT, int_exit);
 	signal(SIGTERM, int_exit);
 
-	if (bpf_set_link_xdp_fd(ifindex, prog_fd[prog_num], xdp_flags) < 0) {
+	prog = bpf_object__find_program_by_title(obj, prog_name);
+	if (!prog) {
+		fprintf(stderr, "bpf_object__find_program_by_title failed\n");
+		return EXIT_FAIL;
+	}
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		fprintf(stderr, "bpf_program__fd failed\n");
+		return EXIT_FAIL;
+	}
+
+	if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) {
 		fprintf(stderr, "link set xdp fd failed\n");
 		return EXIT_FAIL_XDP;
 	}
 
-	stats_poll(interval, use_separators, prog_num, stress_mode);
+	stats_poll(interval, use_separators, prog_name, stress_mode);
 	return EXIT_OK;
 }